1. Field of Invention
The present invention relates generally to a semiconductor wafer processing apparatus. More specifically, the invention relates to a dielectric etch processing chamber having improved thermal and by-product management capabilities, improved control of gaseous species residence time, and an expanded process window including high flow rates and low operating pressures.
2. Background of the Invention
One challenge facing all forms of semiconductor processing is the industry wide progression towards decreasing feature sizes resulting in rapidly shrinking critical dimensions. Current design rules have feature sizes of less than about 0.18 microns and feature sizes below about 0.1 microns are being developed.
Another challenge facing semiconductor processing is the trend towards smaller footprint devices. One approach to achieving a smaller device footprint is to build the device structure vertically and in some devices, fabricating portions of the device in the substrate itself.
These challenges generate a need for processing applications capable of fabricating high aspect ratio structures and structures with critical dimensions approaching the sub-0.1 micron range.
In view of these challenges, minimizing particulate contamination during the myriad processing sequences used to fabricate an electronic device is critical. Chamber components are selected and processes are performed in reduced atmospheres to assist in reducing and managing particles that may be present and/or generated in the processing environment. Of particular importance is the management of films that form within the process chamber during wafer processing.
Films deposited within the processing chamber are major contributors to the total particulate concentrations found within the process chamber. Films typically form on exposed chamber and process kit components during a wide variety of semiconductor processing applications.
During dielectric etch processes, for example, some of the material removed from the layer exposed to the etchant is exhausted from the processing chamber. However, some etch reaction by-products form deposits on exposed chamber surfaces and on surfaces of the etched structure.
The deposits on chamber surfaces increase in thickness as the process cycles are repeated and additional wafers are processed. As the deposit thickness increases, so too does the internal stresses associated with the deposit. Additional stresses are created in these deposits due to differences in thermal expansion rates between the deposit and the chamber surfaces. Conventional etch chambers lack appropriate thermal management techniques to reduce thermally induced stresses between accumulated deposits and chamber components. Eventually, the stresses can cause the deposits to crack, consequently releasing particles into the chamber environment. These film particles may impinge upon the wafer surface, typically creating a defect in the circuit structure on the wafer.
Control of deposit formation on the etch structure is also a critical process consideration. In high aspect ratio dielectric etch processes, for example, the formation of a thin sidewall layer or passivation layer is desired to help maintain sidewall profile control as the depth of the etched feature increases. As feature sizes decrease, however, sidewall profile control becomes increasingly more difficult and possibly unfeasible using conventional plasma etch chambers. Decreasing critical dimensions require increasingly refined control of an expanded range of etch process chemistry parameters not provided by conventional etch chambers.
Therefore, there is a need for a dielectric etch processing apparatus with the capability of providing expanded processing capabilities with improved process parameter control that enables advanced feature dielectric etch processes.
The disadvantages associated with the prior art etch chambers and the challenges posed by advanced dielectric etch processes are overcome by embodiments of the present invention of a thermally controlled plasma etch chamber having an expanded process window and improved byproduct management capabilities. The inventive procees chamber is generally a capacitively coupled plasma source chamber and, more specifically, a capacitively coupled chamber operating in an RIE mode and MERIE mode.
An embodiment of an apparatus according to the present invention comprises a thermally controlled reactor for plasma etch processing substrates at subatmospheric pressures, comprising: a vacuum chamber having a gas inlet, a gas outlet and an interior surface; a thermally controlled liner disposed adjacent to said interior surface said thermally controlled liner having an internal fluid passageway; a thermally controlled substrate support disposed within said vacuum chamber; and temperature of said gas inlet is different said thermally controlled liner.
Another embodiment of an apparatus according to the present invention comprises a thermally controlled reactor for plasma etch processing substrates at subatmospheric pressures, comprising: a vacuum chamber having a gas inlet, a gas outlet and an interior surface; a liner disposed adjacent to said interior; a thermally controlled substrate support disposed within said vacuum chamber; a vacuum pump system having capacity of at least 1600 liter per minute.
Another embodiment of an apparatus according to the present invention is a thermally controlled reactor for plasma etch processing substrates at subatmospheric pressures, comprising: a vacuum chamber comprising a processing volume with a lid, a wall, a gas inlet, a gas outlet disposed within said processing volume, said wall having an interior surface; a thermally controlled liner disposed adjacent to said interior surface said thermally controlled liner having an internal fluid passageway; and a thermally controlled substrate support disposed within said processing volume, said thermally controlled substrate support having multiple temperature control zones.
Another embodiment of an apparatus according to the present invention is a thermally controlled plasma processing chamber, comprising: a vacuum chamber comprising a chamber interior; a gas inlet for providing a gas into said chamber interior; a plasma excitation power source coupled to said vacuum chamber so as to excite a portion of the gas within said chamber interior into a plasma; an exhaust channel coupling said chamber interior to an exhaust pump and providing a gas flow path between the chamber interior and the exhaust pump; a substrate support disposed within said chamber interior; a thermally controlled liner disposed within said chamber interior, said thermally controlled liner having an integrally formed fluid channel; a deflector positioned within the exhaust channel so as to cause turbulence in the gas flow between the chamber interior and the exhaust pump; and a magnet system disposed adjacent to the deflector.
Another embodiment of an apparatus according to the present invention is a thermally controlled plasma processing chamber, comprising: a vacuum chamber comprising a chamber interior; a gas inlet for providing a gas into said chamber interior; a plasma excitation power source coupled to said vacuum chamber so as to excite a portion of the gas within said chamber interior into a plasma; an exhaust channel coupling said chamber interior to an exhaust pump and providing a gas flow path between the chamber interior and the exhaust pump, said exhaust channel comprising: an inlet aperture coupled to said chamber interior; an outlet aperture in communication with the vacuum pump; a wall between said inlet aperture and said outlet aperture including a protrusion extending into said exhaust channel; a substrate support disposed within said chamber interior; a thermally controlled liner disposed within said chamber interior, said thermally controlled liner having an integrally formed fluid channel; and a deflector positioned within the exhaust channel so as to cause turbulence in the gas flow between the chamber interior and the exhaust pump; and a magnet system disposed adjacent to the deflector.
An embodiment of an etch method according to the present invention is a method of plasma etching features on an oxide layer on a substrate disposed in a thermally controlled plasma etch chamber, comprising: disposing a substrate in a processing region of a thermally controlled plasma etch chamber; controlling the temperature of a wall disposed adjacent to the processing region of the thermally controlled plasma etch chamber; controlling the temperature of a substrate support; maintaining a pressure in the processing region; flowing a gas composition through a thermally differentiated nozzle and into the processing region; coupling RF energy into the processing region to form a plasma from the gas composition; and providing a magnetic field transverse to a pumping annulus in communication with the processing region.
An embodiment of an etch method according to the present invention is a method of plasma etching features on an oxide layer on a substrate disposed in a magnetically enhanced thermally controlled plasma etch chamber, comprising: disposing a substrate in a processing region of a thermally controlled plasma etch chamber; controlling the temperature of a wall disposed adjacent to the processing region of the thermally controlled plasma etch chamber; controlling the temperature of a substrate support; maintaining a pressure in the processing region; flowing a gas composition through a thermally differentiated nozzle and into the processing region; coupling RF energy into the processing region to form a plasma from the gas composition; and providing a magnetic field in the processing region and transverse to the substrate.
Another embodiment of an etch method according to the present invention comprises: disposing a substrate in a processing region of a thermally controlled plasma etch chamber; controlling the temperature of a wall disposed adjacent to the processing region of the thermally controlled plasma etch chamber; controlling the temperature of a substrate support; maintaining a pressure in the processing region; flowing a gas composition into the processing region; coupling RF energy into the processing region to form a plasma from the gas composition; providing a magnetic field in the processing region and transverse to the substrate; and evacuating the chamber at a rate of at least 1600 liter per minute.